I have a Redcat FX-150, I've tried to adjust the idle on it but I just can't get it to idle smoothly, I get a rough idle, it quits and sometimes backfire. With as much adjusting I've done on the carb, I'm getting the feeling that it is the spark plug that is causing the trouble. Is that possible? (noob question). I adjusted the gapping to .025 and even tried it at .027 and I get different idles each time but not a smoth idle as my other fx-150 has.

Any ideas?

 

The fx150's are noted for bad intakes. Check the rubber boot for cracks. I am not saying this is it, but give it a shot.

 

Is the intake where the breather meets the carb? If so, then I've already had the airbox off and I inspected the hose to the carb, it was fine. I removed the outer breather element and re-oiled the inner element. Didn't seem to make a hill-o-beans difference in the idle after I took the airbox cover off.

 

the intake attaches to the front of carb and bolts to top of motor. Two 10 mm nuts I believe. The hose clamp has a notch in it. Take that off and alot ofthem have split right by that notch.

 

Also have you messed with the air mixture at all? Turn it all the way in and come out 1.5 turns or so and adjust from there.

 

Ok, I'll remove the carb and check the intake tonight.

Yea, I messed with the mixture alot. I warmed it up, then ran the screw all the way in and then back out about 2 turns then began messing with the idle. I had to run the idle way in to get a higher RPM and then the miture about 5 or 6 turns out to get the idle to settle down after tapping the gas. It was even worse with the mixture screwed in.

Thanks for the info, I'll be getting new plugs today also so I'll just work sequentially through the plugs and the intake issues to see where the problem lies.

More tonight...

 

Well, it was the plug. I replaced the junky "Torch" plug for a C7HSA, set the mixture to 1 and a half turns and reduced the idle and not a hiccup, no rough idling and best of all, no stalling. Started up on the first try and never quit.

If I have any other issues I'll take off the carb and clean it out, but as for now, I think the problem is solved!

What a difference cheap versus good plugs make!

 

Glad to hear you found a fix KCRider, I have read another post from some one here( cant remember who/where). Had the same problems as you and found the same fix. I replaced the chinese plug in my wifes quad with a ngk c7hsa before ever starting it. I have to wonder how many problems with chinese quads is because of the stock spark plug.

 

I suggest NGK's for all ATVS.... The plugs that ship with the Chinese bikes are more or less a plug to keep dirt & grime out of the cylinder until it gets to the end user...not really a "spark" plug IMO..if you know what I mean heh. I would say 95% of engine troubles with Redcats, Kazumas or Yamotos can lead back to the spark plug or a simple carb cleaning.